In the preparation of soybean milk, great efforts have hitherto been made to deactivate lipoxydase, i.e., an enzyme producing the grassy-smell of soybean which is recognized once soybean milk is drunk.
On the other hand, soybean contains a substantial amount of trypsin inhibitor. This enzyme trypsin inhibitor, which is difficult to deactivate by heating, will inhibit the activity of trypsin, i.e., a digestive enzyme to be secreted in the stomach, so that indigestion or diarrhea may thereby be caused.